Do you guys with 02 have a brown and grey wire coming out of the top of the alternator?

My Truck-1999 Step Side, 5.3 auto with 02 pcm nelson tune.
current problems: flashing battery light in message center, "Generator f terminal dtc"

After looking at my wiring schematics between the 02 PCM and the 99PCM, The differance I found is;
1) 2002, It looks like the C2 (Red) circuit #23, pin# 52 is supposed to have a grey wire that goes to the alternator for the "generator filed duty cycle signal"?
2) the 99 has a blank pin #52
I'm not sure how the 99 accomplishes this because it doesn't have the grey wire out of the alternator. Only 1 brown one. Does the duty cylce not exist on the 99? The 52 pin circuit 23 is empty on the 99 pcm. The brown wire is the same out of both alternators.

The 145 amp alternator wasn't an option during the 99 year so i'll have to see if not having a duty cycle signal is going to create problems when I add a 145 amp alt.

Either I try to add the wire to the 02 pcm and harness or is there a way to delete the terminal form the 02 pcm?

If Wrecked 99-02 trucks existed up here I would buy a whole new harness. But I have very little resources.

All because of False Knock

 

Im glad someone is working on this problem. I have the same things going on and sometimes ABS lights. Hopefully we can come up with something to fix these lights...

 

Creed, why did you change your pcm?

 

If he changed his like me it was because of the false knock. My 00 PCM was showing up to 8 deg knock for no reason. I switched to a stock 02 PCM and all the knock was gone, not to mention it just seems to run better.

 

where did you get it from and how much $$$? Also, does it allow you to turn off your headlights at night?

 

I have a 00 so I already have those features but I got mine for like 40 bucks online. I think it was car-parts.com.

I think 99silver5.3 did the same thing and gained control over his lights etc.

But you will probably have the problems we have. Which is flashing battery light and ABS lights lighting up sometimes. Besides that the PCM works fine.

 

I too am a victim of the 99 PCM...7.9* KR ever since the cam/springs. Stupid PCM thinks that the spring harmonics is detonation...gettin a dyno tune at TTP this Saturday, hopefully they can iron it all out.
I think you need to change the BCM to get control over the lights. I wired an LED in place of the photodiode and made mine full manual. Did it right at the BCM, took about 5 minutes.

 

i have a 2002 and i have a grey and brown wire on the alternater plug. i think 99silver5.3 put a 2002 pcm in his 99. he did say that his batt light comes on but it is working and charges. you might give him a pm and see.

 

Thanks I firgure the flashing battery light is because the pcm is trying to get a signal from the grey wire That isn't there on the 99 wiring.

Thanks, I have been in touch with him,
https://ls1tech.com/forums/showthrea...ghlight=02+pcm
https://ls1tech.com/forums/showthrea...ghlight=02+pcm
I went with the 02 From Nelson because of the 8* kr after the cam/spring swap. It also pulled the timing down to 10, giving me mid 14 sec times. Worse times than before the cam swap. After the 02 pcm swap upgrade it runs real strong, netting me my recent 13.7 sec times.

I don't know if I will try a 99 ever again. I might see if a dyno tune will work but I don't think so. I might get a used 99 and give a wirl while holding on to Nelson 02 tune.


Thats about it, I guess getting ahold of 2002 wiring or deleting the pin from the pcm will be the olnly way to get rid of the flashing battery light.

This whole thing seems ridiculous. There guys throwing ls1 into evrything and I just simply want a ******* light to go away.